My mom has dementia and went to the bathroom in her bed. Is it really an accident or is she just pretending?

Does anyone else wonder if MOM/DAD or? does something on purpose? I know I am probably being paranoid but case in point. This Morning I gave mom some water because she was coughing at around 7:30- I have RA and cannot move till I take meds so told her I would be back the usual time around 8:30 to get her up and I would probably be able to move by then (after my meds worked a bit). I did not smell anything at that time(sorry to be gross)ANyhow , at 8:30 when i went back in(her room is right acroos from mine) I knew she had gone to the bathroom and more than just pee. Although she said that's all she had. What a mess! I will spare you all the gory details. She has dementia, so i know she gets confused but she is usually not too bad in the morning. She could have called me, she knows i would have come and put he on the commode. I know she has peed out of spite, she once told me so in the hospital,so my mind gets wondering did she really know and did it on purpose because I made her wait to get up, or on the other hand she also does a BM in bed sometimes when she is having a blood pressure drop problem so did she just think it was ok?? As you can see I am bugged this morn by this. I cleaned he up in bed the best I could and gave her a shower just to be sure.It has not started out as a good day. Do you think she knows what she did or what, anyone else ever have this problem? Help!!